In the construction industry, it is frequently necessary to construct handrails on the tops of platforms to reduce of risk of workers falling from the platforms, the handrails thereby facilitating the safety of the workers.
A common example of this relates to the use of such platforms in the form of concrete wall panels (slabs). These are used, for example, to shore up road-side trenches or other ground cavities. The panels often have upper extremities at raised elevations, and this can give rise to hazardous situations where workers are required to walk along the tops of the panels.
A known method of constructing handrails for such panels involves the use of welded frames with portions that rest on top of the panels, handrail posts extending upwards from those portions, and legs extending downwards from those portions on the two opposite sides of the panels. The legs serve to retain the handrails in place on the panels, and to keep the posts in substantially upright positions.
However, it is often necessary to build up ground-fill and concrete on at least one side of such panels. Such concrete can foul and damage the legs, and prevent them from being removed, when such removal is desired.
A known method of attempting to avoid this is to insert a barrier or substance such as foam against the wall and legs of the handrail to act as a liner to separate the ground-fill or concrete from the wall. This is to allow the handrail to be removed even after such ground-fill or concrete has set.
However, the legs, when removed, leave voids and these need to be filled, for example, with grout. This is labour intensive, time-consuming and hence also costly in terms of man-hours.
In addition, sometimes, the foam does not adequately protect the legs and these become jammed by the set concrete, thereby necessitating cutting off of the legs in order to remove the handrails. Again, this can contribute to inconvenience and cost.
A method that has been used to attach handrails to such slabs is to drill holes in the slabs and attach anchor bolts to the slabs for attachment of handrail supports. However, a problem with this method is that often, the holes are drilled immediately above reinforcing steel which has been cast into the slabs when they are formed, as such steel cannot be seen when commencing the drilling.
The depth to which the holes need to be drilled is typically greater than the depth at which the reinforcing steel is embedded in the concrete. Therefore, such holes are usually not suitable for their purpose, and other holes need to be drilled instead. Often, a number of unusable holes are drilled during this process.
Apart from the fact that this is labour-intensive, time-consuming and costly, when drilling such unusable holes, the drills often connect with the reinforcing steel, thus causing it to be exposed to the environment. In order to protect the integrity of the steel, the holes need to be suitably sealed. This, in turn, involves further labour, time and cost.
In addition, often the sealing is not effective, with the result that the reinforcing steel is exposed to the environment. This, in turn, can result in moisture penetrating the slabs, causing rusting of the steel, and concrete cancer, thereby significantly reducing the useable lifespan of the slabs.
It is an object of the present invention to ameliorate or overcome the disadvantages of the prior art or to provide a useful alternative thereto.